A method and a device determine a surface temperature of an inductively heated roller shell. A current is induced in the roller shell by an induction coil. An actual value of the surface temperature is determined from at least one measured parameter of an electrical circuit of the induction coil by means of stored data. In order to be able to determine shell temperatures of the roller shell that are as exact as possible without large dispersion, the induction coil is connected to a capacitor in the electrical circuit in order to form an oscillating circuit, wherein the oscillating circuit is operated at an alternating-voltage frequency in the range of 3000 Hz to 30,000 Hz.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method of determining a surface temperature of an inductively heated roller shell, comprising: measuring at least one electric parameter of an oscillating circuit in an operating phase or a quiescent phase of the oscillating circuit, the oscillating circuit being configured with an induction coil and a capacitor for inducing a current in the inductively heated roller shell, the oscillating circuit operating with an alternating voltage frequency in a range from 3,000 Hz to 30,000 Hz; and determining an actual value of the surface temperature based on the measured at least one electric parameter of the oscillating circuit and stored reference data.
2. The method as claimed in claim 1 , wherein the at least one electric parameter that is measured is an inductance of the induction coil in the operating phase of the oscillating circuit or the quiescent phase of the oscillating circuit.
3. The method as claimed in claim 1 , wherein the at least one electric parameter that is measured is a current and a voltage of the oscillating circuit in the operating phase of the oscillating circuit.
4. The method as claimed in claim 3 , wherein measuring the at least one electric parameter includes measuring the current and the voltage of the oscillating circuit following an expiry of a transient phase of the oscillating circuit, and determining an effective value of the current and an effective value of the voltage during a measuring phase.
5. The method as claimed in claim 1 , further comprising: using the induction coil as a heating coil for heating the inductively heated roller shell.
6. The method as claimed in claim 5 , further comprising: using the actual value of the surface temperature to control the heating coil.
7. A device for determining a surface temperature of an inductively heated roller shell, comprising: a measuring device for measuring at least one electric parameter of an oscillating circuit in an operating phase or a quiescent phase of the oscillating circuit, the oscillating circuit being configured with at least one induction coil and a capacitor for inducing a current in the inductively heated roller shell, the oscillating circuit being further configured with a voltage module for generating an alternating voltage with a frequency in a range from 3,000 Hz to 30,000 Hz; and an evaluation apparatus for determining an actual value of the surface temperature based on the measured at least one electric parameter of the oscillating circuit and stored reference data.
8. The device as claimed in claim 7 , wherein the measuring device has a measuring means for measuring an inductance of the induction coil.
9. The device as claimed in claim 7 , wherein the measuring device has a current measuring apparatus for measuring a current of the oscillating circuit, and a voltage measuring apparatus for measuring a voltage of the oscillating circuit.
10. The device as claimed in claim 7 , wherein the voltage module of the oscillating circuit is coupled to a control apparatus, and wherein the control apparatus is configured to activate and deactivate the voltage module.
11. The device as claimed in claim 10 , wherein the device is integrated into a qodet, wherein the godet includes a coil holder, and wherein the induction coil is formed as a heating coil that is held on the coil holder at a short distance from the inductively heated roller shell.
12. The device as claimed in claim 11 , wherein the control apparatus is connected to the evaluation apparatus, and wherein a comparator is integrated into the control apparatus or the evaluation apparatus to provide an actual-intended comparison of surface temperatures of the inductively heated roller shell.
13. The device as claimed in claim 7 , wherein the induction coil has a number of windings in a range from 10 to 50.
14. A method of determining a surface temperature of an inductively heated roller shell, comprising: inducing a current in the inductively heated roller shell by an oscillating circuit, the oscillating circuit being configured with at least one induction coil and a capacitor for inducing the current in the inductively heated roller shell, the oscillating circuit operating with an alternating voltage frequency in a range from 3,000 Hz to 30,000 Hz; measuring at least one electric parameter of the oscillating circuit in an operating phase or a quiescent phase of the oscillating circuit; and determining an actual value of the surface temperature based on the measured at least one electric parameter of the oscillating circuit and stored reference data.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
May 2, 2014
September 4, 2018
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